Technical Abstract:
Paratrichodorus allius, a vector of the tobacco rattle virus which causes corky ringspot disease (CRS) on potato, was isolated from potato fields in Pasco, WA, and Umatilla, OR. Both isolates reproduced successfully on crops commonly rotated with potato as well as most weeds associated with this crop in the Pacific Northwest. Our field data showed that there were varying degrees of resistance to CRS in seven potato cultivars and breedin clones. However, this resistance to disease was not correlated with reproduction of P. allius in the greenhouse. The average reproductive factor (RF = final number of nematodes divided by initial inoculum in 55 days) of P. allius from Umatilla was 10-fold greater than the Pasco isolate on the selected potato cultivars.